Secondary batteries have high applicability depending on the product group and excellent electrical characteristics such as high energy density, and thus are commonly being used as electric power sources of electric vehicles (EVs) or hybrid vehicles (HVs) as well as mobile devices. These secondary batteries have a primary advantage of greatly reducing the use of fossil fuels. Also, secondary batteries do not generate by-products that come with the energy consumption, and thus are environmentally friendly and can improve the energy efficiency. For these reasons, secondary batteries are gaining attention as alternative energy sources.
Generally, a battery pack for EVs includes an assembly made up of a plurality of batteries (cells) or a plurality of assemblies. The cell has a cathode current collector, a separator, an active material, an electrolyte, an aluminum thin-film layer, and the like, and can be charged and discharged by electrochemical reactions between these components or elements.
In addition to the basic structure above, the battery pack further includes a battery management system (BMS) to manage the batteries by monitoring the state of the batteries and controlling the environment of the batteries using algorithms for controlling the power supply based on a driving load of a motor, measuring the electrical properties such as current or voltage, controlling the charge/discharge, equalizing the voltage, estimating the state of charge (SOC), and the like.
Recently, there is an increasing need for a battery pack as high capacity applications as well as energy storage applications. To meet the need, a multi-module battery pack having a plurality of batteries connected in series/parallel is generally dominant.
This multi-structure battery pack may be implemented variously depending on the type of a logic circuit or printed circuit board (PCB). For example, to improve the monitoring and control efficiency, the multi-structure battery pack may comprise a multi-slave BMS including a plurality of slave BMSs to respectively manage a plurality of batteries constituting the battery pack and a main or master BMS for integrated control of a plurality of the slave BMSs.
In this instance, the master BMS communicates with the slave BMSs to collect data of the batteries managed by the slave BMSs that will be used in checking the current state of the batteries and controlling the charge/discharge of the batteries.
To collect data or transmit a command signal, a node identifier (ID) of each slave BMS is necessarily required. Conventionally, an ID is preset on a circuit or programmed in an electrically erasable programmable read-only memory (EEPROM) and the like, for each slave BMS.
Since this conventional method needs mechanisms for operating individual hardware or software as many as the number of slave BMSs included in the battery pack and must manage the mechanisms, it occupies a lot of resources and has a complex operating scheme.